The present invention relates to apparatus for compacting powdered materials preparatory to sintering.
The compacting of pieces to be sintered is generally effected by means of presses which compact the powder at a relatively low speed. These presses operate by applying force to their rams of a magnitude great enough to compact the powder to a sufficiently high density so that the piece to be sintered may have acceptable strength. The magnitude of the force required for compacting the powder varies directly with the cross sectional area and height of the part to be produced.
These requirements therefore demand presses which, on the one hand, are capable of exerting enormous pressures on their rams and, on the other hand, are proportioned to the dimensions of the pieces to be sintered. Therefore, to produce compacts of different sizes a whole range of presses is needed, the installation of which requires an enormous capital investment and the use of which is often limited.
Moreover, with the known presses, both cam-actuated and hydraulically actuated, it is generally not possible in a single compacting operation to exceed a density of about 6.7 kg/dm.sup.3 in the case of iron powder. This density is generally insufficient for pieces which must withstand high stresses or frequent or violent shocks so that it is often necessary after sintering to coin the parts.